5-8. sebaceous glands ___________ glands ________________________ glands that discharge an oily...
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Sebaceous Glands
• ___________ glands• ________________________ glands that discharge an oily lipid
secretion into hair follicles• Simple branched alveolar glands- communicate with a single follicle
and share a duct• Produce large quantities of lipids as they mature• Released through holocrine secretion- rupture of secretory cells
Lipids
• Enter the _________________ of the glands• ____________________________ muscles squeeze the sebaceous
gland and force the lipids into the hair follicle and surface of skin• _______________- secreted lipid; mix of triglycerides, cholesterol,
proteins and electrolytes• Inhibits growth of bacteria, lubricates and protects keratin of hair shaft, and
conditions surrounding skin
Sebaceous Follicles
• Glands not associated with hair follicles• ________________ discharge _______________ directly onto
epidermis• Located on face, back, chest, nipples and external genitalia
Apocrine Sweat Glands
• Armpits, around nipples, and in pubic region• Secrete products into _____________________________• Coiled, tubular• Produce a sticky, cloudy, and potentially odorous secretion• Rely on _______________________ secretion• Begin secreting at puberty• Sweat produced is a nutrient source for bacteria• Myoepithelial cells surround the secretory cells and contract and squeeze the
gland• Controlled by _____________________ system and circulating hormones
Merocrine (eccrine) Sweat Glands
• Coiled, tubular• Discharge secretions directly onto surface of skin• Adults have 2-5 million – __________________ and ____________
have the most• ____________________ perspiration• 99% H2O
Functions of Merocrine Glands
• Cooling surface of skin to reduce body temp- ___________________ perspiration• Excreting water and _________________________• Providing protection from environmental hazards by discouraging MO
growth• Flushing them from surface or making difficult for them to adhere• _____________________- peptide with antibiotic properties
Other Glands
• _______________________- interaction b/t sex hormones and pituitary hormones control secretion• ______________________- passageway of external ear• Secretions combine with nearby secretion glands to form cerumen
Control of Gland Secretions
• ANS controls sebaceous and ____________________ sweat glands• Commands affect all glands of that type• ________________________ glands are more precisely controlled
Nails
• Protect exposed ________________ surfaces of tips of fingers and toes• Help limit distortion of digits when subjected to mechanical stress
Parts of Nails
• _____________________- visible portion; covers nail bed• Dead, tightly compressed cells packed with keratin
• Nail bed- recessed deep to level of surrounding epithelium• Bound on either side by lateral nail grooves and nail folds• _____________________- distal portion that continues past nail bed• _____________________________- area of thickened stratum
corneum free edge extends over
Parts of Nail
• Nail root- where nail production occurs• Deepest portion lies close to bone
• __________________________- cuticle; portion of stratum corneum of nail root that extends over exposed nail• ____________________- pale crescent; caused by vessels being
obscured
Step 2
• Blood clots or scab forms at surface and restricts entry of MOs• Bulk of clot consists of ________________- protein that forms from blood
proteins• Clot’s color reflects presence of trapped ________________• Cells of stratum germinativum undergo rapid divisions and migrate along
edges of wound• ________________________ remove debris and pathogens
Step 3
• ______________________________-blood clot, fibroblasts, and extensive capillary network• Over time, deeper portions of clot dissolves• ________________________ activity leads to appearance of collagen fibers
and ground substance
Step 4
• __________________ contains abnormally large # of collagen fibers and few blood vessels• Hair follicles, glands, and nerves are replaced by ________________
tissue• Formation of scar tissue completes repair process
Keloid
• _______________ tissue formation that continues beyond requirements of tissue repair• Thick, raised area of scar tissue• Covered by shiny, smooth epidermal surface• Upper back, _____________________, anterior chest, and earlobes
Aging
• ______________________ thins; connection b/t epidermis and dermis weakens• # of Langerhans cells decreases- reduces sensitivity of immune system• Vitamin D3 production declines by 75%-reduced calcium and
phosphate absorption• _______________________ activity declines
Aging cont
• _______________________ activity declines- skin dry and scaly• Blood supply to dermis reduced- skin cool• Hair follicles stop functioning or produce thinner, finer hairs• Dermis thins and elastic fiber network decreases in size• Secondary sexual characteristics in hair and body-fat distribution fade• Skin repairs ______________